This invention relates to Timing Chamber Ignition as it is disclosed and claimed in my U.S. Pat. No. 4,977,873 issued Dec. 18, 1990 and U.S. Pat. No. 5,109,817 issued May 5, 1992, it being an object of this invention to control ignition timing by means of mass changes in the combustible mixture, in order to gain a positive slope proportional to engine load. This invention recognizes ignition delay in the Timing Chamber concept taught by the aforementioned patents that increases when density decreases, producing a timing curve proportional to load but with a negative slope. Said negative slope is corrected as disclosed and claimed in my U.S. Pat. No. 5,297,518 issued Mar. 29, 1994, which has a timing delay but advantageously with a positive slope.
It is an object of this invention to provide an igniter with improved catalytic plasma torch flame distribution. The concept herein disclosed is based upon compression ignition of the charge in the igniter's pre-chamber, induced by timed catalytic reduction of the pre-chamber's activation energy. This produces substantially instantaneous combustion in the pre-chamber and is divided into multiple high velocity torches that efficiently ignite the cylinder chamber charge. The timing of the ignition event is based upon the location of the heated catalyst in the pre-chamber and the mass of the charge inducted into the cylinder.
It is an object of this invention to modify the basic timing curve by means of control which directly affects the catalyst actively. Dynamic modification to the timing event is accomplished by using the catalyst as an in-cylinder hot-wire anemometer. It is another object therefore to employ the activity of the catalyst to control ignition timing inversely proportional to the mass of the combustible charge. It is a primary object of this invention to utilize said hot-wire as an anemometer sensitive to changes in mass of the combustible fuel-air mixture, causing corresponding changes in the hot-wire mass so as to simultaneously function firstly as a catalyst to accelerate and improve combustion, secondly as a timing means to retard ignition when cooler and to advance ignition when hotter, and thirdly to produce a signal responsive to resistance changes in said hot-wire mass to govern control means for fuel injection and the like. This method and igniter replaces conventional spark ignition, including distributor, breaker points, coil and high tension leads, and spark plugs. Advantageously, this inventive concept has no moving parts, no sophisticated controls, and is essentially waterproof as well.
It is an object of this invention to provide an engine ignition system that inherently increases power, by vastly improving ignition. With the present invention the timing event occurs instaneously within the pre-chamber from which confinement the explosive plasma escapes through at least one and preferably through a multiplicity of directive ports. These ports are essentially nozzles that project fingers of plasma flame to cover the entire combustion chamber cross section. In practice, these fingers project tangentially from a circle described about the center axis of the igniter, in a spider-like manner.
It is another object of this invention to provide the same effect as a spark ignited fuel rich pre-chamber, but without the added complexity of a pre-chamber fuel supply. Accordingly, this Catalytic Plasma Torch has an extended lean limit that results in better fuel efficiency and lower emissions than spark ignition.
It is an object to provide an ignition system that is readily adjusted and/or controlled by conventional electrical or electronic means. In carrying out this invention there is a heater element and/or catalyst subject to current control means responsive to temperature, for example air intake temperature.
It is an object of this invention to provide an ignition system that has a low energy requirement while satisfying energy requirement prior to combustion via timed selective ionization of reactants in the pre-chamber. Conventional six or twelve volt current renders the heater element of this igniter fully operative, eliminating high tension coils and protected leads. This is a self timed ignition system, basically a single part per combustion chamber and with no moving parts. This system and igniter with its pre-chamber inherently retards timing with load as normally required, and it is adapted to current control so as to be responsive to mass of the combustible mixture that enters the pre-chamber for properly timed ignition.
From the foregoing it will understood that the heater element is responsive to the mass of the combustible mixture, as it changes during engine operation. Said heater element is itself a small sensitive part that operates at ignition temperatures, utilizing the principle of anemometry. The heater element is placed in a fixed location that will provide optimum light load operation of the engine, i.e. most advanced. In practice it is a hot wire exposed to the surrounding moving gas in such a way as to be cooled by said moving gas. Since the velocity of this gas is commensurate with piston velocity times a ratio, and since the heat removal ability of said moving gas is directly proportional to its mass,then the final temperature of said heater element is inversely proportional to the mass of the combustible charge. This causes ignition delay to increase with increased load, giving the timing curve a positive slope. And, as engine speed increases, so does the gas velocity; and at the same load the net mass passing the heater element remains constant so that the net temperature change remains the same. Therefore, for a given load the ignition delay remains constant in terms of crank angle throughout the speed range. Since the time for combustion decreases with increasing RPM, the timing is advanced with a proportional increase in current. Detonation is readily compenstated for by dropping the current through the heater element in response to a signal from a detonation sensor. Hense, this ignition method and igniter dynamically responds to engine load, as it is specially tailored to each cylinder and its combustion chamber. A feature is the simplicity of reliable controls to compensate for engine speed, and detonation, as may be necessary. Another feature is the inherent compensation for changes in atmospheric pressure. As atmospheric pressure decreases, this system and igniter inherently advances, so as to compensate for altitude and weather changes. Another feature is inherent compensation for engine wear, by lowering the charge density and advancing the ignition event as needed for each individual cylinder. And, temperature is compensated for by employing a resistance temperature detector (RTD) which lowers current through the heater element as the ambient temperature increases.
A feature of this invention is that external flame enrichment is not required for ignition, since the catalytic heater element advantageously modifies the ignition energy requirement. Heater element temperature control is therefore an object of this invention and which is associated with the physical mounting of said heater element. That is, reliability is a prime consideration coupled with the ability to control the temperature of said heater element. To this end the igniter body is a heat sink which draws off heat controlled by an insulator that reliably carries the heater element. Accordingly, heat is dissipated and enables changes in heater element temperature that controls ignition timing.
Another feature of this invention is the non-restrictive pre-chamber/nozzle relationship, it being an object to achieve sonic velocities of flame propagation and distribution into the engine combustion chamber. Heretofore, pre-chamber volume/nozzle area ratios have been choked to ratios ranging between 20/1 to 50/1, whereas this chamber volume/nozzle area ratio is for example 3/1 and typically greater than 2/1. Accordingly, the total area of the nozzles herein are but slightly restrictive in relation to the total volume of the pre-chamber. In practice, the total nozzle area equals the cross sectional area of the pre-chamber, in which case the volume factor is a function of the chamber length. Thus, the ratio under consideration is chamber volume to nozzle area, and by which sonic velocity of flame plasma issues into the engine combustion chamber. This is achieved herein by catalytic conditioned compression ignition of the combustible mixture front that is forced into the pre-chamber. This sonic flame propagation differs from prior art pre-chamber concepts that develop pressure slowly, because a flame emanating from a spark gap propagates at 3 to 8 meters/sec., which is relatively slow as compared to the speed of sound which is inherent in the igniter herein disclosed, ie., the explosive flame propagation that emanates from this igniter.
The igniter herein disclosed is a CATALYTIC PLASMA TORCH (CPT) that is primarily made from non-refractory materials such as brass or mild steel etc., whereas spark ignited pre-chambers heretofore have required basically refractory material supported by high strength steel alloys of nickel or chromium, because of the restrictive 20/1 to 50/1 chamber-nozzle relationship required to build up a high pressure ratio greater than 2/1 propagating from a slow spark ignited flame. The catalytic plasma torch as disclosed herein produces instantaneous flames (in less than one millisecond) and therefore temperatures and pressures inherent therein do not cause high structural and thermal stresses which are persistent in spark ignited pre-chambers.